Non-renewable fuse.



R. C. COLE.

NON-RENEWABLE FUSE. 'APPLICATION FILED 11,411.17, 1913.

R. C. COLE. NON-RENEWABLE FUSE. APPLICATION FILED MAR. 17, 191s.

Patented Oct. 20, 1914.

2 SHEETS-SHEET 2.

AROBERT C. COLE, OF HARTFORD,

Ycitizen of 'the 4United States,

UNTTED sTATEs PATENT oFFicE.

coNnEcTIcUT, nssrsnon To THEJoHNs-PRATT com- ZPANY, OF HARTFORD,CONNECTICUT, A CORPORATION OF CONNECTICUT.

noN-EENEWABLE FUSE.

' Fuses, of which the following isa specification. l This inventionrelates to the construction of inclosed electric safety fuses hayngsingle and multiple fusible links of the ferrule,

' lug and knife blade terminal types.

disrupted .means Itis requiredA that Electric fuses are essentiallyintended to be safety devices. They are designed to be placed inVcircuits and to open on an abnormal'rise of current and thus protectapparatus connected-'with the circuits and yobjects adjacent tothecircuits and the fuses. If theydo not blow'when the conditinsb'ecomedangerous they are not safety devices.

`Mii'ch thought and study has been given and much labor and expense-hasbeen incurred in order to devise fusesthat will blow accurately/underthe predetermined conditions and thus be dependable .safety tliefusibleelements be inclosed in (order-to eliminate the dangers of the openingof the circuits when the fusible elements melt. Fusible elements thatare inclosed cannot be seen. To` save expense unscrupulous persons andthose not skilled in the art frequently after a fuse has blown, insertanew fusible element in place of the one. that has been destroyed. As aresult it often happens that fusible elements of a capacity notwarranted by ther conditions have been placed in fuses and becausethevelements could not be seen these have been passedas safety devices,on the assumption that the elements were of the proper capacity and ofthe rating stated on the fuses, whereas, as a matter of fact the`fusible elements were of so vmuch greater' capacity that the fusesinstead of being safety deidce's were an element of danger.

The object of this invention is to so construct an inclosed fuse thatafter the fusible element originally placed therein has been ordestroyed, the structure cannot be disassembled or manipulated'in suchay manner that another fusible element can be placed in the interior. Toattain this object the fuses are so manufactured that the terminalsafter once assembledl cannotbe removed witliout destroying or causingvisual I. -Shpeciication of Letters Patent. A l' lamination med march1,7, 1913.

vcut in central .Fig. t shows verse section on Awith b-y solder 4, or

Patented oct. 2o, 1914.y .seria1No.754,e22.

damage-to the structure, or cannot be drilled or cutand a fusibleelement passed through the -inside and connected with the terminal so asto complete the circuit through the interior.- The onlywa'y that a fusewhich e'mbodies thisinv'ention can be made use of after it has`beenblown is by connecting the terminals by a link which passes overthe exterior, a" condition which instantly shows that the'fuseis iiot inits original state.

I Figure 1 ofthe accompanying drawingsy is a side View with' part cutin'centralfsection of-a single link inclosed fuse of the ferruleterminal type which embodies the invention. Fig 2 shows a similar viewvof a fuse of thesame type which' is constructed according to thisinvention and is vented in such manner as lto permit the escape of gasesdeveloped by the blowing of the '-fuse, the vent openings being arrangedin such manner that it is practically impossible to pass a' fuse wirethrough them from one terminal to the other. Fig. 3 is a side view withpart section of a multiple link inthe vknife blade terminal type. atransverse section taken on the plane'indicated by the dotted .line 41-4onFig. 3, looking in closed fuse of the direction indicated by thearrows. Fig. 15 is a side View with a part cutin central section of amultiple link inclosed fuse of the knife blade terminal type having adifferent construction fromthat shown inv Figf. lFig. 6 shows atranstlie plane indicated by the dotted line 6-#6 on Fig. 5, looking-.inthe direction indicated bythe arrows.

The fuses shown have nonsconducting `casiugs l which-are desirably madeof tubular pieces of 'vulcanized fiber.vv In the form first shownmetallic end caps "2 are forced on the ends of the casing. may be madeofbrass or steel, as desired, and their inner edges are crimped into thecasing as at 3 so that after .once being set they cannot be withdrawn. vThe closed ends of these caps are inset and connected thereanv otherdesired means are the internal terminals 5 to which the vends of thefusible element '6 are secured.

In the recessed ends of the caps-are steel disks 7. These disksv arecase-hardened or made extremely hard in any other desired manner so thatthey cannotbe punched, drilled or otherwise cut. Itis desirable tolocate brass disks 8 outside of the hard 'steel These end capsv disksand to hold these in place by spinning or otherwise turning the outeredges 9 of the caps over the edges of the disks. As a result of thisconstruction, after a fusible element become disrupted the end capscannot-be removed without destroying the casing and the steel diskscannot be perforated so as to permit a fusible element to be run throughfrom one terminal .to the other. v

1f it is desired to provide vents for the escape of gases when the fuseblows, openings 10 may be made through the end walls of the caps. Inthis case instead of using a flat hardened steel disk, as shown in Fig.1, the hardened steel disk may be cupped as is the disk 11 shown in Fig.2. Vent openings 12 may be made through cup. The cupped disk'is securedby turning over the outer end of the cap. This disk is hardened so thatit cannot be perforated and the vent openings are in such osition thatitis impossible to push a wire t rough them and through the casing andout through the vent openings at the other end and thus electricallyconnect the terminals together in the interior.

In the form shown in Figs. 3 and 4 the knife blade terminals 13 areconnected with an anchoringspider 14 that tits Within the casing. Theinternal terminals 5 of the fusible element 6 are connected with thisspider which is attached to the external terminals. On .the outsideofthe ends of the casing tight-fitting ferrules 15 are driven. Theseferrules are desirably tapering and can be made of steel or brass, asdesired, preferably the former. After these ferrules have been forced toplace, pins 16 are driven through them and the casing andterminalanchors. These pins securely hold the terminals and the ferrulesin Vplace on the ends of the casing. Felt washers 17 may be placed overthe ends of the casing and felt rings 1S may be placed around theferrules. Ove-r these .are placed hardened steel caps 19,l which afterbeing located have their inner edges turned in over the edges of theferrules that are held on by the pins. When the edges of the caps arethusturned in ,the parts cannot be removed for the caps cannot bedrawnfrom the ferrules and the ferrules and terminal anchors cannot beremoved becausethey are held by the concealed pins'. The front turned inedges of the hardened steel caps are preferably provided with openings20. vVhen a fusible element blows the gases can` pass through the poresof the washers 17 and rings 18 and escape through these openings in theends of the caps and thus relieve the pressure in the interior.

In the forms shown in Figs. 5 and 6, hardened steel ferrules 21 aredriven on the ends of the casing and ,secured in place by the pins whichpass through the ferrules, the

the sides of thisv casing and the arms of the terminal anchors. Thefront edge of this ferrule is turned up at 23'and on the fer-rule istightly set the end cap 24. The pins lcannot be drivenroutv as` they areconcealed so that they ferrules cannot be removed and the steelnon-drillable caps are set so tightly on the ferrules that they cannotbe removed without destroying or materially damaging the structure.

The' invention claimed is:

1. An inclosed fuse having a fusible element, a casing inclosing saidelement and tool-resisting disks of the hardness of hardened steelpermanently attached to and.

protecting the ends of the casing, whereby perforations cannot be easilycut from the exterior' to the interior through said protecting disks topermit the insertion of a fusible element without substantial damage tothe structure.

2. An inclosed fuse having a fusible element, a casing inclosing saidelement, and

tool-resisting means of the hardness of hardened steel with ventopenings permanently attached to and protecting the ends of the casing,whereby openings cannot be Amade from the exterior to the interiorthrough said protecting means for the insertion of a fusible elementwithout destroying the structure.

' 3. An inclosed fuse having a fusible element, a casing inclosing saidelement, and

tool-resisting disks ofthe hardness of hardened steel permanentlyattached to the ends of the casing and protecting the ends of thefusible element whereby openings cannot be made from 'the exterior tothe interior through vsaid protecting disks for the insertion of afusible element without destroy- Aing the structure.

4. An inclosed fuse having a fusible element, a casing inclosing saidelement, and hardened steel parts permanently attached to and protectingthe ends of the casing so as to render it diiiicult to perforate theprotected ends of the casing for the renewal of the vfusible element.

5. An inclosed fuse having a fusible element, a casing inclosing saidelement, an means closing the ends of the casing, said means havinghardened steel parts permanently attached to 'and obstructing theopenings into the ends of the casing, whereby openings cannot be madeinto the ends of the casingfor the insertion of a fusible elementwithout destroying the structure.

6. An inclosed fuse having a fusible element, a casing inclosing saidelement, ferrules on the ends of said casing and hardened steel diskspermanently attached to the .ferrules and protecting the ends of saidcas- An inclosed fuse having a fusible element, a casing inclosing saidelement, and

hardened steel end Capsl permanently attached to the ends of saideasing, whereby openings oannot be readily drilled` through said endcaps from the exterior' into the ends of the casing so as to permit theinsertion of a Conducting,` element without substantial and ,apparentmutilation of the structure.

8. An inclosed fuse having a fusible element, a easing inclosing saidelement and a tool-resisting disk of the hardness of hardened steelpermanently attached to and proteoting one end of the casing, wherebyperforations cannot be easily out from the eX- terior to the interiorthrough said protect i ing` disk to permit the insertion of a fusibleelement without substantial damage to the structure, and meanspermanently closing the other end of the casing.

9. An inelosed fuse having a fusible element, a casing inelosing saidelement, and a hardened steel end cap permanently attached to one end ofsaid casing, whereby. openings cannot be readily drilled through saidend Cap from the exterior into the und of the easing so as to permit theinsertion of a conducting element Without substantial and apparentmutilation of the stl-nei tui-e, and means permanently closing the otherend of the easing.

ROBERT C. COLE. lVitnesses JOSELHINE M. STREMPFER, HARRY R. VILLIAMS.

